This document, produced by the NSA and the US military’s Joint Functional Component Command – Network Wardare, provides a briefing on, and classification guide to, the highly sensitive group of “core computer network operations secrets” codenamed SENTRY EAGLE: see the Intercept article Core Secrets: NSA Saboteurs in China and Germany, 10 October 2014.

This undated presentation from NSA’s UK-based Menwith Hill station describes the various uses of open source intelligence (OSINT) in computer network operations, including the monitoring of hacker forums and spotting opportunities for so-called “Fourth Party Collection”: see the Intercept article XKEYSCORE: NSA’s Google for the World’s Private Communications, 1 July 2015.

This 2010 presentation and speaking notes from the NSA’s Office of Legal Counsel explains the legal authorities governing the agency’s computer network operations (CNO) activities: see the New York Times article Hunting for Hackers, N.S.A. Secretly Expands Internet Spying at U.S. Border, 4 June 2015.